1 2 /* 3 * Copyright 2007 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10 #include "bmpdecoderhelper.h" 11 #include "SkImageDecoder.h" 12 #include "SkScaledBitmapSampler.h" 13 #include "SkStream.h" 14 #include "SkColorPriv.h" 15 #include "SkTDArray.h" 16 #include "SkTRegistry.h" 17 18 class SkBMPImageDecoder : public SkImageDecoder { 19 public: 20 SkBMPImageDecoder() {} 21 22 virtual Format getFormat() const { 23 return kBMP_Format; 24 } 25 26 protected: 27 virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode); 28 }; 29 30 static SkImageDecoder* Factory(SkStream* stream) { 31 static const char kBmpMagic[] = { 'B', 'M' }; 32 33 size_t len = stream->getLength(); 34 char buffer[sizeof(kBmpMagic)]; 35 36 if (len > sizeof(kBmpMagic) && 37 stream->read(buffer, sizeof(kBmpMagic)) == sizeof(kBmpMagic) && 38 !memcmp(buffer, kBmpMagic, sizeof(kBmpMagic))) { 39 return SkNEW(SkBMPImageDecoder); 40 } 41 return NULL; 42 } 43 44 static SkTRegistry<SkImageDecoder*, SkStream*> gReg(Factory); 45 46 /////////////////////////////////////////////////////////////////////////////// 47 48 class SkBmpDecoderCallback : public image_codec::BmpDecoderCallback { 49 public: 50 // we don't copy the bitmap, just remember the pointer 51 SkBmpDecoderCallback(bool justBounds) : fJustBounds(justBounds) {} 52 53 // override from BmpDecoderCallback 54 virtual uint8* SetSize(int width, int height) { 55 fWidth = width; 56 fHeight = height; 57 if (fJustBounds) { 58 return NULL; 59 } 60 61 fRGB.setCount(width * height * 3); // 3 == r, g, b 62 return fRGB.begin(); 63 } 64 65 int width() const { return fWidth; } 66 int height() const { return fHeight; } 67 uint8_t* rgb() const { return fRGB.begin(); } 68 69 private: 70 SkTDArray<uint8_t> fRGB; 71 int fWidth; 72 int fHeight; 73 bool fJustBounds; 74 }; 75 76 bool SkBMPImageDecoder::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) { 77 78 size_t length = stream->getLength(); 79 SkAutoMalloc storage(length); 80 81 if (stream->read(storage.get(), length) != length) { 82 return false; 83 } 84 85 const bool justBounds = SkImageDecoder::kDecodeBounds_Mode == mode; 86 SkBmpDecoderCallback callback(justBounds); 87 88 // Now decode the BMP into callback's rgb() array [r,g,b, r,g,b, ...] 89 { 90 image_codec::BmpDecoderHelper helper; 91 const int max_pixels = 16383*16383; // max width*height 92 if (!helper.DecodeImage((const char*)storage.get(), length, 93 max_pixels, &callback)) { 94 return false; 95 } 96 } 97 98 // we don't need this anymore, so free it now (before we try to allocate 99 // the bitmap's pixels) rather than waiting for its destructor 100 storage.free(); 101 102 int width = callback.width(); 103 int height = callback.height(); 104 SkBitmap::Config config = this->getPrefConfig(k32Bit_SrcDepth, false); 105 106 // only accept prefConfig if it makes sense for us 107 if (SkBitmap::kARGB_4444_Config != config && 108 SkBitmap::kRGB_565_Config != config) { 109 config = SkBitmap::kARGB_8888_Config; 110 } 111 112 SkScaledBitmapSampler sampler(width, height, getSampleSize()); 113 114 if (justBounds) { 115 bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight()); 116 bm->setIsOpaque(true); 117 return true; 118 } 119 #ifdef SK_BUILD_FOR_ANDROID 120 // No Bitmap reuse supported for this format 121 if (!bm->isNull()) { 122 return false; 123 } 124 #endif 125 bm->setConfig(config, sampler.scaledWidth(), sampler.scaledHeight()); 126 bm->setIsOpaque(true); 127 128 if (!this->allocPixelRef(bm, NULL)) { 129 return false; 130 } 131 132 SkAutoLockPixels alp(*bm); 133 134 if (!sampler.begin(bm, SkScaledBitmapSampler::kRGB, getDitherImage())) { 135 return false; 136 } 137 138 const int srcRowBytes = width * 3; 139 const int dstHeight = sampler.scaledHeight(); 140 const uint8_t* srcRow = callback.rgb(); 141 142 srcRow += sampler.srcY0() * srcRowBytes; 143 for (int y = 0; y < dstHeight; y++) { 144 sampler.next(srcRow); 145 srcRow += sampler.srcDY() * srcRowBytes; 146 } 147 return true; 148 } 149
